The Human Gene Mapping project involves intramural and extramural collaborations with several groups of the scientific community. The Genetics Section has developed efficient facilities for establishing and maintaining this program through different approaches and methodologies. These include (1) the creation and maintenance of a hybrid cell panel, following hybridization of somatic cells of human and rodent origins and hybrid selection in special culture media, (2) biochemical and karyological characterizations of cell lines, (3) in situ hybridization of molecular clones to human metaphase chromosomes, (4) detection of restriction fragment length polymorphisms (RFLP) by screening human DNAS, and (5) linkage estimates by pedigree analysis and statistical analysis of concordance and discordance using a cell panel. Other techniques have also included the use of polymerase chain reaction amplification and electrophoretic analysis of RNA or protein binding products. Altogether these approaches have enabled us to map a number of disparate products such as proto-oncogenes, growth factors, tumor-related products, cell receptors, members of the immunoglobulin superfamily, and chemotactic substances. The principal investigator serves in the human genome projects as an elected member of the Human Genome Organization (HUGO) as well as on the committee on Comparative Gene Mapping. Some 15 collaborative projects are continuously being carried out at any time due to the extensive interaction with members of the scientific community. These collaborations have resulted in several publications and participations in local and International meetings.